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author | Florian Dold <florian.dold@gmail.com> | 2017-05-03 15:35:00 +0200 |
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committer | Florian Dold <florian.dold@gmail.com> | 2017-05-03 15:35:00 +0200 |
commit | de98e0b232509d5f40c135d540a70e415272ff85 (patch) | |
tree | a79222a5b58484ab3b80d18efcaaa7ccc4769b33 /node_modules/react-dom/lib/accumulateInto.js | |
parent | e0c9d480a73fa629c1e4a47d3e721f1d2d345406 (diff) |
node_modules
Diffstat (limited to 'node_modules/react-dom/lib/accumulateInto.js')
-rw-r--r-- | node_modules/react-dom/lib/accumulateInto.js | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/node_modules/react-dom/lib/accumulateInto.js b/node_modules/react-dom/lib/accumulateInto.js new file mode 100644 index 000000000..8ea8f9e12 --- /dev/null +++ b/node_modules/react-dom/lib/accumulateInto.js @@ -0,0 +1,57 @@ +/** + * Copyright 2014-present, Facebook, Inc. + * All rights reserved. + * + * This source code is licensed under the BSD-style license found in the + * LICENSE file in the root directory of this source tree. An additional grant + * of patent rights can be found in the PATENTS file in the same directory. + * + * + */ + +'use strict'; + +var _prodInvariant = require('./reactProdInvariant'); + +var invariant = require('fbjs/lib/invariant'); + +/** + * Accumulates items that must not be null or undefined into the first one. This + * is used to conserve memory by avoiding array allocations, and thus sacrifices + * API cleanness. Since `current` can be null before being passed in and not + * null after this function, make sure to assign it back to `current`: + * + * `a = accumulateInto(a, b);` + * + * This API should be sparingly used. Try `accumulate` for something cleaner. + * + * @return {*|array<*>} An accumulation of items. + */ + +function accumulateInto(current, next) { + !(next != null) ? process.env.NODE_ENV !== 'production' ? invariant(false, 'accumulateInto(...): Accumulated items must not be null or undefined.') : _prodInvariant('30') : void 0; + + if (current == null) { + return next; + } + + // Both are not empty. Warning: Never call x.concat(y) when you are not + // certain that x is an Array (x could be a string with concat method). + if (Array.isArray(current)) { + if (Array.isArray(next)) { + current.push.apply(current, next); + return current; + } + current.push(next); + return current; + } + + if (Array.isArray(next)) { + // A bit too dangerous to mutate `next`. + return [current].concat(next); + } + + return [current, next]; +} + +module.exports = accumulateInto;
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